Non-insulin dependent diabetes mellitus (NIDDM) is a major source of morbidity and mortality in the United States, affecting 13-16 million Americans. Women appear to be disproportionately affected, with particularly high prevalence and associated morbidity among African- American women. Obesity has been implicated as a primary factor in the etiology of NIDDM and weight loss is recommended as a principal intervention for obese diabetic individuals. Although behavioral obesity treatments produce weight losses and improve glycemic control, they have achieved only modest long-term success, particularly among African-American women. The investigators pilot data indicate that the addition of the overall objective for this proposed project is to determine whether the addition of motivational interviewing to a behavioral weight control program for NIDDM produces significantly greater long-term improvements in glycemic control and weight loss than a standard behavioral weight control program in a sample of black and white women. The investigators propose to recruit a total of 160 women (50 percent African-American) aged 40 or older with NIDDM who are overweight (body mass index between 27 and 45). Participants will be randomized to one of two treatment conditions: 1) behavioral weight control with motivational interviewing (BT+MI); or 2) behavioral weight control with health education attention control (BT+HE). Primary outcome measures to evaluate treatment efficacy will by glycemic control and without loss at 6-, 12- and 18-month follow-up. Secondary measures obtained at each assessment point will include: 1) treatment adherence (e.g., group attendance, self-monitoring, dietary change physical activity, and medication adherence); 2) change in cardiovascular disease risk factors (e.g., fat distribution, lipids, and blood pressure); 3) mood and attitudinal measures; 4) health-related quality of life; and 5) intervention costs.